Mold and mold making method



F55. 24, 1942. F, v, HART MOLD AND MOLD MAKING METHOD Filed Oct. 51,1938 /NV[NTUR ED STATE Patented Feb. 24, 1942 PATENT OFFICE MOLD ANDMOLD MAKING METHOD Fred V. Hart, Lynn, Mass., assignor to United I ShoeMachinery Corporation, Borough of Flemington, N. J a corporation of NewJersey Application October 31, 1938, Serial No. 237,917

7 Claims.

..This invention relates to the reproduction of a model andisexemplified herein with reference to a mold and molding process foruse in producing duplicate and geometrically similar but reversedreproductions of a model.

In many. arts, as in that of shoemaking, for example, it is oftendesirable to employ a form or shaping member to assist in thepreliminary shaping of shoe parts, which form or member is to have thesameshape as, or a shape related to, that of a last or a part thereof.Commonly, as. in .the case of shoemaking,'such forms are used in pairscomprising exactly similar right fand left forms each of which is themirror image of th other. Forms of the type referred to may be made by acut and try method comprising the steps of making a pattern as nearlylike the model as possible as judged by the eye and with the aid ofsuitable measurements, and then making a casting in the usual way by theuse of the pattern. However, this method of making a pattern is subjectto the disadvantages of expense and inaccuracy entailed by a largeamount of hand work; and these disadvantages are aggravated in theproduction of a 'pair of right and left forms, especially if only onemodel,

a right or left, is available, because of the dimculty of making twopatterns which are'exactly alike as to size and the different parts ofwhich are disposed in exactly opposite relation so'that the patterns aretrue rights and lefts.

In view of the foregoing, itis a general object of this invention toobviate the difficulties referred to above and to provide an improvedmold and molding method by the use of which it is possible to makedirectly a pattern which is a duplicate of a model and a second patternwhich is a reversed or mirror-image reproduction of the model, therelation between the duplicate and reversed reproduction of the modelbeing the same, for example, as that between right and left lasts orlike sections thereof.

To this end, the invention. provides a mold having templates shaped inconformity to a series of contours of a model, the templates beingmounted so as to beheld in the same relation as that between thecontours or in a reversed relaby providing filling material, such as aself hardening plastic material between the templates, the fillingmaterial being smoothed so that its surface is continuous with andincludes the shaped edges of the templates. Thus, the result-,

ing mold surface will have a form exactly com-- plementary to that ofthe model and upon being filled with a moldable pattern material impartsto the latter the exact form of the model. After in engagement with eachother, the templates being arranged in making a mold for a duplicate.

the pattern has hardened and has been removed from the mold, it may beused in the usual .way in making a casting which is. an exact duplicateof the model. 1

The positioning. of the templates in the above manner is facilitated bythe use of. two sets of positioning surfaces adapted to be selectivelyheld of the model so that one set of positioning surfaces are inengagementwith eachother, the other set of positioning surfacesbeingheld in engagement with each other when the templates arerearranged to produce a mold for a reversed reproduction of the model.

In another aspect the invention provides methods of making a mold of anyof the types referred to above.

A These and other features of the invention will I appear more fullyfrom the following detailed description when read in connection with thev accompanying drawing and will be pointed out by the use of which themethod disclosed herein tion, a mold surface in each case extendingbetween the templates. Thus, since. the same templates are used inmaking a mold for both a duplicate and reversed reproduction of themodel, corresponding parts of the reproductions are exactly alike inshape but have a true right and left relation to each other.

The mold surface may conveniently bemade in the appended claims.

In the drawing,

Fig. 1 is a view in perspective of an illustrative mold made inaccordance with the invention and duction of a modelill (Fig. 4), forexample, is

efl 'ected by the. use of a mold the essential feature of which consistsin the provision of a series oftemplates I! (Fig, 1), I! (Fig. 2) eachof which has a surface defining an edgewhich is shaped in conformity toone of a series of contours such as It (Fig. 4) of the model III, thetemplates being arranged in the construction of the mold so that therelation between-their shaped edges 'is the same as or similar contoursof the templates.

to that between the various contours ll.

For purposes of illustration, the contours H as illustrated herein areformed by the intersection of equally spaced parallel planes with thesurface of the model III, the planes extending crosswise of the model;but it is to be understood that the invention contemplates the use oftemplates shaped in accordance with contours havmg any suitable relationto the model, the relation between the templates as arranged in the moldbeing the same as, or similar to, the relation between the contoursthemselves.

In both of the embodiments of the invention illustrated in Figs. 1 and 2the positioning of the templates in the manner referred to above iseffected by the use of sets of positioning surfaces on the templates andholder or positioning member. In the mold illustrated in Fig. 1 thetemplates l2 are mounted side-by-side in contact with each other, theirends constituting positioning surfaces and being in alinement with eachother when the shaped edges of the templates are positioned properlywith respect to each other. The templates are thus held between thesides ii of a box l1, which serves as holder or positioning member, thebox having ends l8 which are engaged by the endmost templates andprevent the templates from separating laterally. If, as in the mold ofFig. 1, the templates l2 have a thickness equal to the spacing of thecontours l4 and are mounted side-by-side in contact with each other,their shaped edges being formed midway between the sides of thetemplates at the vertex of chamfered surfaces 20 (Fig. 3) extendinginwardly of the templates from their sides, the relation of the shapededges of the templates l2 longitudinally of the box I! is the same asthe relation between the contours longitudinally of the model. Theshaped edges of the templates 1 2 are so formed that they also have thesame heightwise relation as that between the contours l4 when the bottomedges of the templates l2 are seated onthe bottom of the box.

Illustrative of other ways in which the arranging of the templates maybe effected within the scope of the invention, reference will now bemade to an alternative mold construction illustrated in Fig. 2. Thetemplates l2 of this mold, after being formed in the same manner asdescribed above in connection with the mold of Fig. 1, are assembledbetween end covers- 22 the provides a mold having a surface which isexactly complementary to the model and also a molding method by the useof which an exact' duplicate of the model can be made.

In making a geometrically similar but reversed or mirror-imagereproduction of the model l which may also be termed an enantiomorphicbottom edges of the covers 22 and the templates l2 being in the sameplane and having recesses 24 which are in alinement with each other whenthe shaped edges of templates are in their proper relation. The grooveformed by the alined'recesses 24 is adapted to receive a holder or po-'sitioning member in the form of a bar 26 the sides of which fit closelywithin the sides of the recesses 24. The templates l2 are prevented fromseparating from each other by clamps 28 adapted to bear against thecovers 22 and to be adjustably fixed to the bar 26 by set screws 29.-

The templates l2 or 12' now having beenarranged so that their shapededges have the same relation to each other as that between the contoursof the model, the mold of either Fig. 1 or Fig. 2 is next completed byforming a continuous smoothly curved mold surface defined by the Thisfeature of the construction of ,the molds results from the use, asillustrated in Fig; 3 for example, of filling material 30 placed betweenthe chamfered surreproduction, the templates l2 and [23 0f the moldconstructions illustrated in Figs. land 2, respectively, are assembledin the same order as before but are turned end for end. In thusrearranging. the mold of Fig. 1, for example, the templates l2 areremoved from the box I] one by one and turned so that the positions ofthe ends of each template are interchanged, the ends of the templatesagain being held in alinement with each other by the sides of the boxIE. Thus, corresponding contours of the reproduction made from theoriginal mold illustrated in Fig. 1 and the rearranged-mold are exactlyalike but .are in a true right and left or mirror-image the bar 26,turned end for end, and repositioned 1 on the bar, the latter beingreceived in the recesses 24. It is to be .understood, of course, in

connection with both types of molds that a new mold surface is formed inthe manner described above after the templates l2 or l2. have beenreversed and that a reproduction made from such a mold will differ fromthe model only in being a "rightf' reproduction, if the model isa"left,"'or

vice versa. Each is the mirror image or enantiomorphic reproduction of.the other. Although for the sake of convenience the templates.|2 aremade to fit closely between the sides of the'box l1 and the recesses 24and templates.l2' are formed so as to receive the bar 26 witha closelit, the positioning of the templates in the case of either moldcan beaccomplished so long as there are two sets of positioning surfaces onthe templates and the holder or positioning member in the case of eachmold. For

example, and with reference to a single template l2 of the mold of Fig.1, one end of a template and the adjacent side of the "box may beconsidered as constituting one set of positioning surfaces, the otherend of the template and the same side of the box constituting the secondset of positioning surfaces which'are to be brought into engagement witheach other when the template is tumed end for end. Similarly, it mayalso be considered that the one end of a template l2 and one. side ofthe box "constitute one set of positioning surfaces and that the sameend of this template and the other side of the box constitute the secondset of positioning surfaces.

' It is thus apparent that the positioning of the templates, to provideeither a right or left mold may, if desired, be effected by the use ofeither a box having only one side and templates having form of a beeffected when they are either in their normal or reversed positions byinsuring that the same sides of all of the recesses 24 are in engagementwith oneside or the other of the bar 26 if, for

the purpose of facilitating the rearrangement of the templates, it maybe'desirable that the width of the recesses 21 be substantially greaterthan that of the bar 26.

Having thus described my invention, what .I claim as new and desire tosecure by Letters Patent of the United States is:

1. That improvement in, methods of making duplicate and reversedreproductions of a model which consists in forming a plurality oftemplates in conformit toa series of contoursv of the model formed bythe intersection'therewith of a plurality of parallel planes, arrangingsaid templates 'so that their contours have the same relation to eachother as that between the corresponding contours of the model, forming amold surface between said templates, forming an impression of said moldsurface .thereby producing a duplicate of the model, removing said moldsurface from said templates, turning each of said templates end for endbut maintaining their relation otherwise the same as before,

forming a second mold surface between said templates and forming animpression of the second mold surface thereby producing a similar butreversed reproduction of the model.-

2. That improvement in methods of making duplicate and reversedreproductions of a model which consists in forming a plurality oftemplates in conformity to a series of contours of responding contoursof the model, forming a continuous mold surface defined by saidtemplates, forming an impression of said mold surface thereby producinga duplicate of the model, removing said mold surface from'saidtemplates, rearranging the templates in the same order but so that thepositions of the ends of each temthe model formed by the intersectiontherewith of a plurality of parallel planes, each template 4 having apositioning surface, arranging said templates so that when theirpositioning surfaces are in alinement the contours of said templateshavethe same relation to each other as that between the correspondingcontours of the model, forming a' mold surface between said templates,forming an impression of saidmold surface thereby producing a duplicateof the model, removing said mold surface from said templates,rearranging said templates in the same order and with their positioningsurfaces in alinem'ent but each template being turned end for end,forming a second mold surface between said reversed templates, andforming an impression of said second mold surface thereby producing asimilar but reversed reproduction of the model. i I

3. That improvement in methods of making duplicate and reversedreproductions of a model which consists in forming a plurality oftemplates in conformity to a series of contours of the model formed bythe intersectiontherewith of a plurality of parallel planes, arrangingsaid templates with their ends in alinement with'each other and so thattheir contours have the same relation to each other as that between thecorplate are interchanged, forming a second co tinuousmold surfacedefined by said templates,

and forming an impression of said second mold surface thereby producinga similar but reversed reproduction'of the model.

4. A mold comprising a plurality 'of templates which are recessed toprovide edges shaped in conformity to a series of contours of an asymmetric model, said edges defining sectional contours of the cavity ofthe mold and extending continuously between opposite points on the rimof the cavity, a holder for said templates effec- -tive to maintain themin assembled position with the .relation between their edges and thecontours of the model the same to produce a duplicate of the model, andmeans disposed in the spaces between the shaped edges and cooperatingwith said edges to form a smooth continuous 'molding' surface at saidedges.

5. A mold vcomprising a plurality of templates I "having recesses theedges of which are shaped in conformity to a series of contours of anasymmetric model, said edges being elements of the surface of the cavityof the mold and extending continuously between opposite points on therim of the cavity, a holder for said templates arranged to maintain themin assembled position with the relation between their edges and thecontours of the model reversed to produce a" opposite points on the rimof the mold cavity defined by said templates, reversing each of thetemplates and assembling them so that their edges are in enantiomorphicrelation'to said series of contours of the model, thereby to formportions of the surface of a mold for forming an enantiomorphicreproduction of the model.

7. That method of making a reversed or mirror-image reproduction of amodel which consists in forming recesses in a plurality of templates toprovide edges which conform to a series of sectional contours of themodel and which extend continuously between the opposite 4 points on therim of the mold cavity defined by said recesses, arranging the templatesso that said edges form a series which is the mirror image of saidseries of contours of the model,

and-filling the space between the edges with material to form a smoothsurface of which the edges are elements, whereby a smooth surfaced moldis formed in which a reversed or mirrorimage reproduction ofthe modelcan be molded.

FRED V. HART.

